The present invention relates to a system and garment that incorporates sensors that can be used for measuring or monitoring pressure or forces in feet, the stumps of limbs of an amputee that are fitted with prosthetic devices, or any other parts of the body that are subject to forces such as the buttock while seated or when external pressure inducing devices are employed, for example, pressure bandages. The invention may also incorporate other sensors for monitoring physical conditions such as temperature, strain, stress or angulation or sensors for monitoring physiological conditions such as the makeup of sweat or body exudate. Moreover, the invention also relates to a method to monitor or diagnose any foot or limb related activity for recreational, sporting, military or medical reasons and is particularly aimed at the treatment of neuropathic or other degenerating conditions.
Diabetes, alcoholism, uremia, AIDs, or nutritional deficiencies are conditions that are well known as causing damage to nerve endings known as peripheral neuropathy. Other less common causes include exposure to cold or radiation, physical injuries, a few medicines, toxic substances, vascular or collagen disorders, systemic lupus erythematosus, scleroderma and rheumatoid arthritis. Symptoms of peripheral neuropathy are usually in the form of pain, numbness, tingling, burning or a loss of feeling. The symptoms may also include a sensation that you are wearing an invisible glove or sock; a burning or freezing pain; sharp, jabbing or electric pain; and an extreme sensitivity to touch.
Diabetes also affects the circulation. Poor circulation can affect the ability of the body to heal when damage occurs. Healing can take a while and it is imperative that pressure is removed from the area and good wound dressings are used, infections can spread, the ultimate of this process is an amputation. Neuropathy is the commonest complication of diabetes and usually arises within 5 years of the onset of the disease. Fifty percent of patients with neuropathic joints require some degree of amputation within 5 years.
Patients with peripheral neuropathy demonstrate a significant increase in loading time, mainly at the heel and at the metatarsal area of the foot, and they demonstrate a reduction at the hallux: i.e. they become flat footed and acquire a hip-based walking strategy. It has been established from discussions with leading world podiatrists and clinicians that a means for obtaining early diagnosis or identification of at risk patients would be of enormous advantage enabling early intervention to assist patients with long term solutions. What is required is a device that can provide a measured record of daily activity at the foot.
One attempt to address this problem is the Pedar system which is a pressure mapping system developed by Novel, Munich Germany. The system monitors local loading of the foot inside the shoe and is used for:                gait analysis        rehabilitation assessment        shoe research and design        aiding in shoe prescription and orthotic design        field testing of sport applications        kinetic analysis of free gait        
However, the system is not suitable for elderly or frail persons, or extended wearing by persons with venous illnesses such as diabetes. The other serious limitation is that these devices are shoe inserts and are therefore only effective when the person is wearing shoes. It is however desirable to gather information for all walking behavior with and without shoes.
Another attempt is described in German patent DE10314211 which relates to a sock that has a grid of conducting yarns that provide pressure measuring at points of intersection when a person is walking. The pressure-sensitive material extends over the entire foot region and provides an insight on the distribution of loads but does not measure pressure or loads in absolute terms nor does it measure other factors such as temperature and strain.